Transition metal sulfides (TMS) are well known catalysts that have a wide range of applications. For example, TMS catalysts are useful in hydrotreating petroleum feedstocks to remove heteroatoms in the feed, such as sulfur, oxygen and nitrogen. Such TMS catalysts can be used in hydrogenation processes, alcohol synthesis from syngas, hydrodemetallization of heavy crudes, catalytic hydrocracking and the like.
Currently, the majority of sulfur compounds in distillates are removed by conventional hydrodesulfurization (HDS) technology using conventional TMS catalysts. HDS at low hydrogen partial pressures is associated with extremely unfavorable kinetic conditions: poisoning by high levels of nitrogen, severe hydrogen starvation, and low concentrations of sulfur vacancies (catalytically active sites) on the catalysts. Hence, conventional HDS processes run at low pressures (e.g., 50-100 psig, 344.74 kPa-689.48 kPa) remove stearically hindered sulfur, also referred to as hard sulfur, at impractically slow rates, and hence require large capital outlays in order to meet emissions requirements.
Ruthenium sulfide is known to be much more active than conventional HDS catalysts. However, the catalyst is prohibitively expensive. Hence, it is surely desirable to enhance the cost effectiveness of this catalyst.